Wheel-drive assembly

ABSTRACT

A wheel drive assembly for transferring propelling torque from a source shaft to a wheel, the source shaft receiving torque from a motion actuator. The wheel drive assembly includes a wheel-hub, adapted to have the wheel mounted thereon, the wheel-hub being arranged about a longitudinal axis, which is adapted to coincide with a rotation axis of the wheel. The wheel drive assembly further includes a drive axle and a constant velocity (CV) joint mounted onto an outer end of the drive axle. The CV joint connects the drive axle to the wheel-hub. An outermost surface of the CV joint is disposed outwardly of an outermost surface of the wheel hub, along the longitudinal axis of the wheel-hub.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of: (i) U.S. application Ser. No.17/529,335, filed on Nov. 18, 2021, which is incorporated herein byreference; and (ii) PCT/IB2021/057921, filed on Aug. 30, 2021, which isincorporated herein by reference. PCT/IB2021/057921 claims priority toIsrael Patent Application No. IL277061 filed on Aug. 31, 2020, which isincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to vehicle wheel drives, and particularlyto a wheel-drive assembly that transfers propulsive torque from a sourceto a vehicle wheel.

BACKGROUND OF THE INVENTION

In most vehicles, propelling torque from a motion actuator, e.g. anelectric motor, an engine, or a transmission gear, is transferred towheels of the vehicle using drive assemblies. Typically, each driveassembly transfers torque from the motion actuator located on thechassis of the vehicle to a wheel on one side of the chassis.

FIGS. 1A and 1B (PRIOR ART) are schematic exploded view illustrations ofa typical drive assembly. As seen, a typical drive assembly 10 includesa wheel-hub 12, adapted to have a wheel 14 mounted thereon. Wheel 14typically includes a tire 16 and a tire rim 18, the tire rim beingconnected, or connectable, to wheel-hub 12, for example using aplurality of fasteners such as lug nuts.

A drive shaft 19, typically extends under the chassis of a vehiclebetween the engine and the wheel hub, and typically includes a driveaxle 20, which is also known as a half-shaft, functionally associatedwith a first constant velocity (CV) joint 22 and with a second CV joint24. First CV joint 22, also known as an inboard CV joint, isfunctionally associated with an input shaft 26, adapted to connect to anoutput of the motion actuator, and to receive propelling torquetherefrom. Second CV joint 24, also known as an outboard CV joint, isfunctionally associated with an output shaft 28, which is connected, orconnectable, to wheel-hub 12. Consequently, drive axle 20, together withCV joints 22 and 24, transfers torque from the motion actuator to wheel14, while allowing angular displacement between a rotational axis of theoutput shaft of the motion actuator and a rotational axis of wheel-hub12. Such angular displacement may be caused by motion of the wheel invarious, non-rotating directions, such as vertical travel of the wheelcaused by uneven road surfaces.

US Patent Application Publication 2005/0257971 relates to a motor-drivenwheel includes a wheel disc, a wheel hub, a knuckle, a hub bearing, aconstant-velocity joint, an in-wheel motor, and a spring. The center ofswing of the constant-velocity joint is placed closer to the outside ofthe vehicle relative to the hub bearing. Since such components of theconstant-velocity joint as an inner race, balls and a cage are placeddifferently in position from the hub bearing, the hub bearing can bereduced in diameter. An outer race of the constant-velocity joint isintegrated with the wheel hub into a single part and has an openingfacing the outside of the vehicle. Since the opening is large andshallow, the work of installing the cage, balls and inner race andsecuring them with a snap ring is facilitated.

SUMMARY

According to an aspect of some embodiments of the present inventionthere is provided a wheel drive assembly for transferring propellingtorque from a source shaft to a wheel, the source shaft receiving torquefrom a motion actuator, the wheel drive assembly including:

a) a wheel-hub, adapted to have the wheel mounted thereon, the wheel-hubbeing arranged about a longitudinal axis, which is adapted to coincidewith a rotation axis of the wheel;b) a drive axle; andc) a constant velocity (CV) joint mounted onto an outer end of the driveaxle, the CV joint connecting the drive axle to the wheel-hub,

wherein an outermost surface of the CV joint is disposed outwardly of anoutermost surface of the wheel hub, along the longitudinal axis of thewheel-hub.

In some embodiments, the drive axle includes a half shaft.

In some embodiments, wherein the CV joint includes a housing and a cageaccommodated within the housing. In some embodiments, the wheel-hubincludes a seat at an outer side thereof, and wherein the housingengages the seat. In some embodiments, the housing engages the wheel-hubfrom an outer side of the wheel-hub.

In some embodiments, the housing is separable from the wheel hub. Insome embodiments, in use of the CV joint, bearings of the CV joint areadapted rotate about an interior surface of the housing.

In some embodiments, a majority of the CV joint is exposed exteriorly tothe wheel hub.

In some embodiments, the wheel-drive assembly further includes an innerCV joint mounted onto an inner end of the drive axle, and adapted to befunctionally coupled to the source shaft.

According to another aspect of some embodiments of the present inventionthere is provided a wheel assembly, including:

a wheel drive assembly as disclosed herein; and

a wheel including a tire and a tire rim, the tire rim mounted onto thewheel-hub,

wherein at least a portion of the CV joint is visible from an outer sideof the wheel.

In some embodiments, the wheel assembly further includes a disk brakeand caliper, wherein at least a portion of the CV joint is exterior tothe disk brake.

In some embodiments, an outermost surface of the cv joint extendsoutwardly of a central portion of the tire rim. In some embodiments, theoutermost surface of the CV joint extends outwardly of the majority ofthe tire rim. In some embodiments, the outermost surface of the CV jointextends outwardly of the entirety of the tire rim.

In some embodiments, the wheel assembly further includes, or isfunctionally associated with, a steering assembly adapted to steer thewheel hub about a steering pivot point, wherein the steering pivot pointdoes not coincide with a pivot point of the CV joint.

In some embodiments, when the steering assembly steers the wheel hub ata steering angle δ, the CV joint swings at a swing angle γ, swing angleγ being smaller than steering angle δ. In some embodiments, a ratiobetween swing angle γ and steering angle δ is not greater than 1:1.5.

According to yet another aspect of some embodiments of the presentinvention there is provided a vehicle, including:

a chassis;

at least one motion actuator, functionally associated with the chassis,the motion actuator having an output shaft; and

at least one wheel assembly as disclosed herein,

wherein the wheel drive assembly of the at least one wheel assembly isfunctionally associated with the output shaft of the motion actuator, asthe source shaft, and the at least one wheel assembly is adapted totransfer propelling torque from the at least one motion actuator to thewheel of the at least one wheel assembly.

In some embodiments, the wheel drive assembly further includes an innerCV joint mounted onto an inner end of the drive axle, the inner CV jointbeing functionally coupled to the output shaft of the motion actuator.In some embodiments, the inner CV joint is disposed at a laterallyexterior edge of the chassis. In some embodiments, the inner CV joint isvertically stationary with respect to the chassis, and the outer CVjoint is vertically movable with respect to the chassis, within apredetermined angular range of the drive axle relative to the chassis.In some embodiments, the motion actuator is attached to the chassis, andfunctions as a sprung mass.

According to a further aspect of some embodiments of the presentinvention there is provided a vehicle, including:

a chassis;

at least one motion actuator, functionally associated with the chassis,the motion actuator having an output shaft; and

at least one wheel assembly, including:

-   -   a wheel-hub arranged about a longitudinal axis;    -   a drive axle;    -   a constant velocity (CV) joint mounted onto an outer end of the        drive axle, the CV joint connecting the drive axle to the        wheel-hub; and    -   a wheel including a tire and a tire rim, the tire rim mounted        onto the wheel-hub such that the longitudinal axis of the        wheel-hub coincides with a rotational axis of the wheel,    -   the wheel assembly being functionally associated with the output        shaft of the motion actuator, as the source shaft, and the drive        axle and CV joint are adapted to transfer propelling torque from        the at least one motion actuator to the wheel; and

a steering assembly, functionally associated with the wheel-hub andadapted to steer the wheel by pivoting the wheel-hub and the wheel abouta steering pivot point, wherein the steering pivot point does notcoincide with a pivot point of the CV joint.

In some embodiments, when the steering assembly steers the wheel hub ata steering angle δ, the CV joint swings at a swing angle γ, swing angleγ being smaller than steering angle δ.

According to yet a further aspect of some embodiments of the presentinvention there is provided a vehicle, including:

a chassis;

at least one motion actuator, functionally associated with the chassis,the motion actuator having an output shaft; and

at least one wheel assembly, including:

-   -   a wheel-hub arranged about a longitudinal axis;    -   a drive axle;    -   a constant velocity (CV) joint mounted onto an outer end of the        drive axle, the CV joint connecting the drive axle to the        wheel-hub; and    -   a wheel including a tire and a tire rim, the tire rim mounted        onto the wheel-hub,    -   the wheel assembly being functionally associated with the output        shaft of the motion actuator, as the source shaft, and the drive        axle and CV joint are adapted to transfer propelling torque from        the at least one motion actuator to the wheel; and

a steering assembly, functionally associated with the wheel-hub andadapted to steer the wheel by pivoting the wheel-hub and the wheel abouta steering pivot point, wherein the steering pivot point does notcoincide with a pivot point of the CV joint,

wherein, when the steering assembly steers the wheel hub at a steeringangle δ, the CV joint swings at a swing angle γ, swing angle γ beingsmaller than steering angle δ.

In some embodiments, a ratio between swing angle γ and steering angle δis not greater than 1:1.5.

In some embodiments, an outermost surface of the CV joint is disposedoutwardly of an outermost surface of the wheel hub, along thelongitudinal axis of the wheel-hub.

In some embodiments, at least a portion of the CV joint is visible froman outer side of the wheel.

In some embodiments, the wheel drive assembly further includes an innerCV joint mounted onto an inner end of the drive axle, the inner CV jointbeing functionally coupled to the output shaft of the motion actuator.In some embodiments, the inner CV joint is disposed at a laterallyexterior edge of the chassis. In some embodiments, the inner CV joint isvertically stationary with respect to the chassis, and the outer CVjoint is vertically movable with respect to the chassis, within apredetermined angular range of the drive axle relative to the chassis.

In some embodiments, the motion actuator is attached to the chassis, andfunctions as a sprung mass.

According to another aspect of some embodiments of the present inventionthere is provided a method for enabling transfer of propelling torquefrom a motion actuator of a vehicle, having an output shaft, to a wheelof the vehicle, using a drive shaft, a the method including:

fastening an outer CV joint of the drive shaft to an outer side of thewheel-hub;

connecting an inner CV joint of the drive shaft to the output shaft ofthe motion actuator; and

mounting a wheel on the wheel hub,

wherein, following the fastening, an outermost surface of the CV jointis disposed outwardly of an outermost surface of the wheel hub.

In some embodiments, the mounting of the wheel on the wheel hub occursprior to the fastening of the outer CV joint.

In some embodiments, the method further includes, prior to thefastening, inserting the outer CV joint into the wheel hub from anexterior side of the wheel hub. In some embodiments, the wheel-hubincludes an outer-side seat, and the inserting of the outer CV jointincludes accommodating the outer CV joint in the outer-side seat.

In some embodiments, the wheel includes a tire mounted onto a tire rim,and the mounting of the wheel on the wheel hub includes fastening thetire rim to the wheel-hub.

In some embodiments, the outermost surface of the outer CV joint extendsoutwardly of a central portion of the tire rim. In some embodiments, theoutermost surface of the outer CV joint extends outwardly of themajority of the tire rim. In some embodiments, the outermost surface ofthe outer CV joint extends outwardly of the entirety of the tire rim.

In some embodiments, the connecting of an inner CV joint includesplacing the inner CV joint at an exterior edge of a chassis of thevehicle.

Unless otherwise defined, all technical and/or scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which the invention pertains. In the case ofconflict, the specification, including any definitions therein, willtake precedence.

As used herein, the terms “comprising”, “including”, “having” andgrammatical variants thereof are to be taken as specifying the statedfeatures, integers, steps or components but do not preclude the additionof one or more additional features, integers, steps, components orgroups thereof. These terms encompass the terms “consisting of” and“consisting essentially of”.

As used herein, the term “or” is a logical operator combining twoBoolean input conditions into a Boolean compound condition, such thatthe compound condition is satisfied if and only if at least one of thetwo input conditions is satisfied. In other words, if conditionC=condition A or condition B, then condition C is not satisfied whenboth condition A and condition B are not satisfied, but is satisfied ineach of the following cases: (i) condition A is satisfied and conditionB is not satisfied, (ii) condition A is not satisfied and condition B issatisfied, and (iii) both condition A and condition B are satisfied.

As used herein, the term “inboard” designates a component of an assemblywhich is at a location or side facing in the direction of the motionactuator (or in the direction of the chassis). Inversely, the term“outboard” designates a component of an assembly which is a t a locationor side facing away from the motion actuator, in the direction of thewheel.

As used herein, the terms “inward” and “interior” relate to a locationor side of a component facing toward, or being closer to, a longitudinalcenterline of a vehicle. Often, components that are further inward, ormore interior, face the motion actuator of the vehicle. Inversely, theterms “outward” and “exterior” relate to a location or side of acomponent facing away from, or being further from, a longitudinalcenterline of a vehicle. Often, components that are further outward, ormore exterior, face the wheel of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the invention are herein described, by way ofexample only, with reference to the accompanying drawings. With specificreference now to the drawings in detail, it is stressed that theparticulars shown are by way of example and for purposes of illustrativediscussion of embodiments of the invention. In this regard, thedescription taken with the drawings makes apparent to those skilled inthe art how embodiments of the invention may be practiced. In thedrawings:

FIGS. 1A and 1B (PRIOR ART) are schematic exploded view illustrations ofa typical prior art drive assembly;

FIG. 1C (PRIOR ART) is a schematic front view representation of avehicle including prior art wheel drive assemblies, as shown in FIGS. 1Aand 1B;

FIG. 2 (PRIOR ART) is a schematic illustration comparing the angulartolerances of drive axles of different lengths;

FIG. 3 is an exploded perspective view illustration of a wheel-driveassembly according to embodiments of the disclosed technology;

FIGS. 4A and 4B are, respectively, a side view illustration and a crosssectional illustration of a wheel-hub forming part of the wheel-driveassembly of FIG. 4, according to embodiments of the disclosedtechnology;

FIG. 5 is a perspective view illustration of a method of connectingcomponents of the wheel-drive assembly of FIG. 3, according toembodiments of the disclosed technology;

FIGS. 6A and 6B are, respectively, front and back perspective viewillustrations of the wheel-drive assembly of FIG. 3 according toembodiments of the disclosed technology, FIG. 6B having a the wheeladded thereto;

FIG. 7 is a partially cut-away perspective view illustration of thewheel-drive assembly of FIG. 3, the cut-away portion revealingcomponents of a CV joint forming part of the wheel-drive assembly;

FIGS. 8A and 8B are sectional illustrations of the wheel-drive assemblyof FIG. 3, FIG. 8A being a close-up of a central portion of FIG. 8B;

FIG. 9 is schematic front view representation of a vehicle includingwheel drive assemblies of FIGS. 3 to 8B, according to embodiments of thedisclosed technology;

FIGS. 10A and 10B are schematic side view illustrations of a wheelconnected to the wheel drive assembly of FIGS. 4 to 8B, in two steeringsituations; and

FIG. 11 is a schematic flow chart of a method for transferringpropelling torque from a motion actuator of a vehicle to a wheel of avehicle, using the wheel drive assembly of the disclosed technology,according to some embodiments thereof.

DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION

The present invention relates to vehicle wheel drives, and particularlyto a wheel-drive assembly that transfers propulsive torque from a sourceto a vehicle wheel.

Technical Aspects Addressed by the Present Invention

In applications such as when using a motor that is located close to thewheel, it is desirable to reduce the distance between the motionactuator, such as a motor or engine, and the wheel. However, even withthe reduced distance, there must be sufficient range of motion betweenthe wheel and the chassis, e.g. for vertical travel and/or for steeringof the wheel.

One way to reduce the distance between the motion actuator and thewheel, or wheel-hub, is by shortening the length of drive axle 20. Asexplained herein, this method may be problematic when CV joints 22 and24 need to compensate for angular movement of the drive axle, caused,for example, by vertical motion of the wheel relative to the chassis.

Reference is now additionally made to FIG. 1C (PRIOR ART), which is aschematic front view representation of a vehicle including prior artwheel drive assemblies, as shown in FIG. 1A. As seen, in a typical priorart vehicle 30, a powertrain 32 of the motor or engine of the vehicle islocated under the chassis 34. Torque is transferred from powertrain 32to wheel 14 via drive axle 20 and wheel-hub 16. In typical prior artdrive assemblies, the second, outboard, the CV joint of drive axle 20 isconnected to an inboard side of wheel-hub 16, and does not extend intothe wheel hub.

Reference is now additionally made to FIG. 2 (PRIOR ART), which is aschematic illustration comparing the angular tolerances of drive axlesof different lengths. In FIG. 2, it is assumed that the motion actuator,e.g. an electric motor, is fixed to the chassis of the vehicle. As such,first (inboard) CV joint 22, which is fixed to the chassis via themotion actuator, is disposed at a fixed height relative to the vehicleplatform (chassis).

When there is a disturbance to the wheel, e.g. the wheel goes into a pothole, the wheel shifts vertically, causing second CV joint 24 to movedownward. When the wheel shifts vertically by a distance d, the lengthof drive axle 20 impacts the angular tolerance required from the secondCV joint in order to accommodate for the vertical motion of the wheel.

As seen in FIG. 2, when the drive axle 20 a has a first length L1 andthe distance between first CV joint 22 and second CV joint 24 a is L1,in order to facilitate a vertical motion of the wheel to a distance d,the drive axle must be disposed at an angle of x degrees from thehorizontal, which must accommodated by second CV joint 24 a. However,when the drive axle 20 b is shorter and has a length L2<L1, the distancebetween first CV joint 22 and second CV joint 24 b is L2. In order tofacilitate a vertical motion of the wheel to the distance d, the driveaxle must be disposed at an angle of y degrees from the horizontal,which must accommodated by second CV joint 24 b. Given that distance dis the same in both scenarios, and drive axle 20 a is shorter than driveaxle 20 b, in accordance with basic geometry, e.g. the Pythagoreantheorem, y>x. As a result, greater tolerance is required from CV joint24 b than from CV joint 24 a.

As such, if the maximal tolerance of the second CV joint is fixedregardless of the length of the drive axle, a longer drive axle allowsthe wheel-drive assembly to accommodate greater vertical distancestraversed by the wheel, than a shorter drive axle. It is possible that asystem including a shorter drive axle would not have sufficienttolerance to accommodate the angular shift (y) associated with aspecific vertical distance, and thus, that shortening the drive axlewould not provide a suitable solution.

There is thus a need in the art for a wheel-drive assembly which has asmall distance between the motion actuator and the wheel, whileaccommodating sufficient range of motion between the wheel and chassis,e.g. for vertical travel and/or for steering of the wheel.

Additionally, the maximal swing angle of a CV joint is typically morelimited than a steering angle of the wheel-hub or wheel. Typically, thesteering angle of the wheel is dependent on motion of the CV joint, andbecause the range of the swing angle is typically smaller than thelargest theoretical steering angle, in practice, the maximal steeringangle is limited by the range of the swing angle.

As such, there is a need in the art for a wheel-drive assembly in whichthe steering angle is decoupled from the CV-joint swing angle.Alternately, there is a need in the art for a wheel-drive assembly inwhich the range of the CV-joint swing angle facilitates a steering anglewhich is greater than the swing angle.

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not necessarily limited in itsapplication to the details of construction and the arrangement of thecomponents and/or methods set forth in the following description and/orillustrated in the drawings and/or the Examples. The invention iscapable of other embodiments or of being practiced or carried out invarious ways.

Reference is now made to FIG. 3, which is an exploded perspective viewillustration of a wheel-drive assembly 100 according to embodiments ofthe disclosed technology. As seen, wheel-drive assembly 100 includes awheel hub 102, adapted to have a wheel 104 mounted thereon. Wheel-driveassembly 100 further includes a drive shaft 105. Drive shaft 105includes a drive axle 106, being functionally associated with a first,inboard, CV joint 108, mounted onto an inner end of the drive axle, andwith a second, outboard, CV joint 110, mounted onto an outer end of thedrive axle. First CV joint 108 is adapted to connect to an output shaftof a motion actuator, and second CV joint 110 is adapted to connectdrive axle 106 to wheel-hub 102. Drive shaft 105 is configured totransfer propelling torque from the motion actuator to the wheel.

Wheel 104 may include a tire rim 112 and a tire 114. In someembodiments, a wheel cover (not explicitly shown) attaches to the tirerim to cover up other components of the wheel-drive assembly, such asthe wheel-hub and/or the CV joint.

In some embodiments, wheel-drive assembly 100, or a wheel assemblyincluding wheel drive assembly 100, includes wheel-brake components,such as a brake disc 116 and a caliper 118.

In some embodiments, drive shaft 105 may be a standard drive shaft, suchas a Rzeppa CV Front Driveshaft commercially available from TeraflexInc. of Utah, USA. In some embodiments, drive shaft 105 may be acustomized or custom-made drive shaft.

Reference is now made to FIGS. 4A and 4B, which are, respectively, aside view illustration and a cross sectional illustration of anexemplary wheel-hub 102 of wheel-drive assembly 100, according toembodiments of the disclosed technology.

As seen, wheel-hub 102 includes an annular wall 120, defining a bore 121and having extending therefrom an inner portion 122 and an outer portion124. Inner portion 122 is generally cylindrical, though a circumscribedbore 126 thereof has a greater diameter at an area distal to wall 120than at an area proximal to wall 120. A circumscribing ring 128surrounds inner portion 122, such that ball bearings 130 are disposedbetween circumscribing ring 128 and inner portion 122.

According to some embodiments, as shown from example in FIGS. 4A and 4B,outer portion 124 is a protruding outer portion which is substantiallycylindrical and extends outwardly from annular wall 120. In someembodiments, the diameter of a bore 132 within outer cowl portion 124 isgreater than the diameter of bore 121. Consequently, a cavity is formedby an outer surface 120 a of wall 120 and surrounding outer cowl portion124. As explained in further detail hereinbelow, surface 120 a defines aseat for a portion of drive shaft 105, disposed within the cavity. Cowlportion 124 terminates in an outward facing surface 134, which is alsothe outermost surface of wheel-hub 102.

In some embodiments, fasteners 136 may be disposed in wall 120,surrounding bore 121 thereof for engagement between wheel-hub 102 andwheel 104.

Reference is now made to FIG. 5, which is a perspective viewillustration of a method of connecting components of wheel-driveassembly 100, according to embodiments of the disclosed technology.

As seen in FIG. 5, drive shaft 105, and more specifically inboard CVjoint 108 thereof, is inserted into bore 132 of cowl portion 124 ofwheel-hub 102, from an outer side thereof, and is moved toward theinterior of wheel-hub 102, e.g. into bores 121 and 126, in the directionof arrow 140. Drive shaft 105 is moved in the direction of arrow 140until a housing 141 of outboard CV joint 110 is disposed within thecavity of cowl portion 124, and engages the seat defined by surface 120a. Fasteners 142 are used to fasten outboard CV joint 110 to surface 120a of wheel-hub 102.

Reference is now additionally made to FIGS. 6A and 6B, which are,respectively, front and back perspective view illustrations ofwheel-drive assembly 100 according to embodiments of the disclosedtechnology, FIG. 6B having wheel 104 added thereto.

As seen, housing 141 of outboard CV joint 110 is disposed withinwheel-hub 102, and specifically within cowl portion 124 thereof, suchthat a portion of the housing, and in some cases a majority of thehousing, is exterior to outermost surface 134 of wheel-hub 102. Stateddifferently, a portion of outboard CV joint 110, and in some embodimentsthe majority of the outboard CV joint, is exposed laterally outside ofwheel-hub 102.

According to some embodiments, for example as shown in FIG. 6A, anoutermost surface 144 of housing 141 is disposed outwardly to outermostsurface 134 of wheel-hub 102, and as a result is disposed outwardly tothe entirety of wheel-hub 102. In this context, fasteners 136 are notconsidered to form part of wheel-hub 102, but rather are separatecomponents adapted to connect wheel-hub 102 to wheel 104. As seen, driveaxle 106 extends through wheel-hub 102, and interiorly beyond the wheelhub, such that inboard CV joint 108 is interior to the entirety ofwheel-hub 102.

Additionally, a portion of CV joint 110, and in some embodiments theentirety of CV joint 110, is disposed exterior to disk brake 116, asseen in FIG. 6B.

As described herein, outboard CV joint 110 is fixedly attached to wheelhub 102 by fasteners 142, and as such propelling torque received bydrive axle 106, is transferred to wheel-hub 102, and to wheel 104, by CVjoint 110.

Reference is now made to FIG. 7, which is a partially cut-awayperspective view illustration of wheel-drive assembly 100, the cut-awayportion revealing components of outboard CV joint 110 of drive shaft 105of the wheel-drive assembly. Reference is additionally made to FIGS. 8Aand 8B, which are sectional illustrations of wheel-drive assembly 100when connected to wheel 104.

As seen in FIG. 7, outboard CV joint 110 includes housing 141, which isfastened by fasteners 142 to annular wall 120 of wheel-hub 102. A cage150 of CV joint 110 is disposed within housing 141, and a boot 152connects cage 150 to drive axle 106 of the drive shaft. Ball bearings ofCV joint 110 are adapted to be disposed in cavities of cage 150, and torotate against an inside surface of housing 141. As seen, there is atleast a portion of inner portion 120 of the wheel-hub into which CVjoint 110 does not extend, and which is not engaged by CV joint 110. Asseen, an inward end of CV joint 110 is disposed laterally outwardly ofan inner most surface of inner portion 120 (along the longitudinal axisof the wheel hub).

As seen, housing 141 abuts, and is seated against, surface 120 a ofannular wall 120, such that a portion of housing 141, and in some casesa majority of housing 141, extends laterally exteriorly to outermostsurface 134 of wheel-hub 102. Additionally, a portion of cage 150, andin some cases a majority of cage 150, extends laterally exteriorly tooutermost surface 134 of wheel hub 102. As seen in FIGS. 5 and 7,housing 141 of CV joint 110 is separable from wheel-hub 102. In thiscontext, the term “separable” mean that the housing can be separatedfrom the wheel-hub, while maintaining its function as a housingsurrounding cage 150.

As mentioned hereinabove, it is a particular feature of some embodimentsof the present invention that the CV joint is separable from, and neednot be integrated with, the wheel-hub. In some embodiments, this mayreduce wear between the wheel-hub and the CV joint, and may easereplacement of the CV joint when it is necessitated by wear of theCV-joint. Additionally, some embodiments of the disclosed technology mayuse “off the shelf” standard CV joints, and the wheel hub may bedesigned to accommodate CV joint of different types and/or sizes.

In some embodiments of the disclosed technology, the materials of thewheel-hub and the CV joint are independent of one another, since thewheel-hub does not engage bearings of the CV-joint. Thus, the selectionof materials for the wheel-hub and CV joint is not constrained byinteraction of CV-joint bearings with the wheel-hub.

In some embodiments of the disclosed technology, the drive shaft may betested independently of the wheel-hub, or externally to the wheel-hub,for example prior to installing the drive shaft.

Turning to FIG. 8B, it is seen that tire rim 112 includes a central wallportion 160, which is fastened to wheel-hub 102. An angled surface 162extends radially and longitudinally outwardly from central wall portion160 to an extremity 164 of the tire rim. A second angled surface 166extends radially outwardly and longitudinally inwardly from extremity164 of the tire rim, and is adapted to have the tire mounted thereon.

As seen in FIG. 8A, outermost surface 144 of housing 141 extendslaterally outwardly of central portion 160 of tire rim 112. In someembodiments, such as the illustrated embodiment, outermost surface 144extends outwardly of the majority of tire rim 112 (in a direction alongthe rotational axis of the tire rim and of the wheel), and in somecases, such as in the illustrated embodiment, extends outwardly ofextremity 164, and thus outwardly of the entirety of tire rim 112.

Reference is now made to FIG. 9, which is a schematic front viewrepresentation of a vehicle including wheel drive assemblies 100,according to embodiments of the disclosed technology. FIG. 9 usesreference numerals similar to those of FIG. 1C.

As seen, in a vehicle 30′ according to the present invention, apowertrain 32′ of the motor or engine of the vehicle is located along anexterior lateral side of the chassis 34, and is fixed thereto. Torque istransferred from powertrain 32′ to wheel 104 via drive shaft 105 andwheel-hub 102. As described hereinabove, the outboard CV joint of thedrive shaft 105 is disposed exterior to wheel-hub 102, such that thedrive axle extends along the length of the wheel-hub. Additionally, theinboard CV joint of the drive shaft 105 is connected to powertrain 32′and as such is disposed at a laterally exterior edge of chassis 34. Theinboard CV joint is fixed to the chassis via powertrain 32′, and isdisposed at a fixed height relative to the chassis.

When there is a disturbance to the wheel, e.g. the wheel goes into a pothole, the wheel shifts vertically, causing the outboard CV joint to movedownward, relative to the chassis, within a predetermined angular rangeof the drive shaft 105.

The connection of the drive axle to the laterally outward side of thewheel-hub, together with the powertrain being installed on the side ofthe chassis, allows for a reduced distance between the powertrain andthe wheel, while maintaining the angular range of the wheels and of theCV joint, as explained herein.

It is a particular feature of the present invention that the placementof drive shaft 105, and particularly the mounting of outboard CV joint110 exteriorly of wheel-hub 102, shortens the distance between thewheel-hub and the motion actuator, relative to a setting in which theoutboard CV joint is attached to an interior side of the wheel-hub. Thisin turn shortens the distance between an exterior side of the wheel andthe motion actuator, or between the exterior side of the wheel and thecenter of the chassis.

However, because drive axle 106 is not shorter than in prior artembodiments, and in fact drive shaft 105 may be an off-the-shelf unit,the angular range that the drive shaft must handle is unchanged relativeto prior art vehicles using the same drive shaft.

As such, the novel placement of the outboard CV joint, as discussedherein, reduces the distance between the wheel and the center of thechassis, or between the wheel and the motion actuator, while addressingthe problem described hereinabove with respect to FIG. 2.

Reference is now made to FIGS. 10A and 10B, which are schematic sideview illustrations of a wheel connected to the wheel drive assembly ofFIGS. 4 to 8B, in two steering situations.

As seen in FIGS. 10A and 10B, wheel 104 is mounted onto wheel-hub 102.Outboard CV-joint 110 of drive shaft 105 is connected to wheel-hub 102,according to the present invention, as described hereinabove. Thewheel-hub, or the wheel, is further connected to a steering assembly170, adapted to steer the wheel-hub and the wheel about a steering pivotpoint 172. The rotational axis of the wheel is indicated by referencenumeral 182.

In the state of FIG. 10A, a longitudinal axis of drive shaft 105coincides with rotational axis 182.

In FIG. 10B, steering assembly 170 has rotated wheel-hub 102 and wheel104 by a steering angle δ. Steering of wheel 104 by angle δ is supportedby rotation of drive shaft 105 by a swing angle γ. Stated differently,to maintain driving of wheel hub 102 by drive shaft 105, longitudinalaxis 184 of drive shaft 105 swings to an angle γ relative to itsposition in FIG. 10A, and relative to the rotational axis 182 of thewheel.

It is a particular feature of the present invention, that because of thenovel placement of CV joint 110 within wheel hub 102, the steering angleδ need not be equal to, and may be larger than, the swing angle γ. Insome embodiments, because of the novel placement of CV joint 110 withinwheel hub 102, the steering pivot point 172 does not coincide with, andis at a distance from, a pivot point of CV joint 110. The angulardifference between steering angle δ and swing angle γ may be due to thedistance between the steering pivot point and the pivot point of CVjoint 110, and/or due to the difference in placement of the swing axison which the drive shaft swings, relative to the placement of thesteering axis on which the wheel-hub, or wheel, is steered.

In some embodiments, the ratio between swing angle γ and steering angleδ is at not greater than 1:1.25, 1:1.5, 1:2, 1:2.5, or 1:3. In someexample embodiments, when steering angle δ is about 25-35 deg, the swingangle γ is about 15-25 deg.

Reference is now made to FIG. 11, which is a schematic flow chart of amethod for enabling transfer of propelling torque from a motion actuatorof a vehicle to a wheel of a vehicle, using the wheel drive assembly ofthe disclosed technology, according to some embodiments thereof.

As seen in FIG. 11, at step 200 an outer CV joint, such as CV joint 110(FIG. 3) of a drive shaft, such as drive shaft 105 (FIG. 3) is fastenedto an outer side of a wheel-hub, such as wheel-hub 102 (FIG. 3).Following the fastening, an outermost surface of the outer CV joint isdisposed outwardly of an outermost surface of the wheel-hub.

At step 202, an inner CV joint of the drive shaft, such as inner CVjoint 108 (FIG. 3) is connected to an output shaft of a motion actuator,such as an output shaft of a motor or drivetrain. In some embodiments,such as the embodiment shown in FIG. 9, connecting of the inner CV jointcomprises connecting the inner CV joint to the motion actuator at anexterior edge of a chassis onto which the motion actuator is fixed.

At step 204, a wheel is mounted onto the wheel hub. As such, when themotion actuator is operated, the drive shaft 105 transfers propellingtorque from the motion actuator to the wheel-hub and the wheel. In someembodiments, mounting of the wheel comprises fastening the tire rim ofthe wheel to the wheel hub.

In some embodiments, step 204 occurs prior to step 200 and/or prior tostep 202.

In some embodiments, at step 208, which occurs prior to steps 200 and202, the outer CV joint is inserted into the wheel hub from an exteriorside of the wheel hub. In some such embodiments, the inner CV joint isslid into an opening in the wheel-hub, from an outer side of thewheel-hub, and is moved in an inward direction, until the outer CV jointengages a surface of the wheel hub. Specifically, the inner CV joint maybe moved until the outer CV joint is accommodated in an outer-side seatof the wheel-hub.

It is expected that during the life of a patent maturing from thisapplication many relevant brake actuators and brake-control-circuitswill be developed. The scope of the terms brake actuators andbrake-control-circuits are intended to include all such newtechnologies, a priori.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable subcombination or as suitable in any other describedembodiment of the invention. Certain features described in the contextof various embodiments are not to be considered essential features ofthose embodiments, unless the embodiment is inoperative without thoseelements.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims.

What is claimed is:
 1. A wheel drive assembly for transferringpropelling torque from a source shaft to a wheel, the source shaftreceiving torque from a motion actuator, the wheel drive assemblycomprising: a) a wheel-hub, adapted to have the wheel mounted thereon,the wheel-hub being arranged about a longitudinal axis, which is adaptedto coincide with a rotation axis of the wheel; b) a drive axle; and c) aconstant velocity (CV) joint mounted onto an outer end of the driveaxle, the CV joint connecting the drive axle to the wheel-hub, whereinan outermost surface of the CV joint is disposed outwardly of anoutermost surface of the wheel hub, along the longitudinal axis of thewheel-hub.
 2. The wheel drive assembly of claim 1, wherein the driveaxle comprises a half shaft.
 3. The wheel drive assembly of claim 1 orclaim 2, wherein the CV joint comprises a housing and a cageaccommodated within the housing.
 4. The wheel drive assembly of claim 3,wherein the wheel-hub includes a seat at an outer side thereof, andwherein the housing engages the seat.
 5. The wheel drive assembly ofclaim 3, wherein the housing engages the wheel-hub from an outer side ofthe wheel-hub.
 6. The wheel drive assembly of any one of claims 3 to 5,wherein the housing is separable from the wheel hub.
 7. The wheel driveassembly of any one of claims 3 to 6, wherein, in use of the CV joint,bearings of the CV joint are adapted rotate about an interior surface ofthe housing.
 8. The wheel drive assembly of any one of the precedingclaims, wherein a majority of the CV joint is exposed exteriorly to thewheel hub.
 9. The wheel drive assembly of any one of the precedingclaims, further comprising an inner CV joint mounted onto an inner endof the drive axle, and adapted to be functionally coupled to the sourceshaft.
 10. A wheel assembly, comprising: a wheel drive assemblyaccording to any one of claims 1 to 9; and a wheel including a tire anda tire rim, the tire rim mounted onto the wheel-hub, wherein at least aportion of the CV joint is visible from an outer side of the wheel. 11.The wheel assembly of claim 10, further comprising a disk brake andcaliper, wherein at least a portion of the CV joint is exterior to thedisk brake.
 12. The wheel assembly of claim 10 or claim 11, wherein anoutermost surface of the cv joint extends outwardly of a central portionof the tire rim.
 13. The wheel assembly of any one of claims 10 to 12,wherein the outermost surface of the CV joint extends outwardly of themajority of the tire rim.
 14. The wheel assembly of any one of claims 10to 13, wherein the outermost surface of the CV joint extends outwardlyof the entirety of the tire rim.
 15. The wheel assembly of any one ofclaims 10 to 14, further comprising, or functionally associated with, asteering assembly adapted to steer the wheel hub about a steering pivotpoint, wherein the steering pivot point does not coincide with a pivotpoint of the CV joint.
 16. The wheel assembly of claim 15, wherein, whenthe steering assembly steers the wheel hub at a steering angle δ, the CVjoint swings at a swing angle γ, swing angle γ being smaller thansteering angle δ.
 17. The wheel assembly of claim 16, wherein a ratiobetween swing angle γ and steering angle δ is not greater than 1:1.5.18. A vehicle, comprising: a chassis; at least one motion actuator,functionally associated with the chassis, the motion actuator having anoutput shaft; and at least one wheel assembly according to any one ofclaims 10 to 17, wherein the wheel drive assembly of the at least onewheel assembly is functionally associated with the output shaft of themotion actuator, as the source shaft, and the at least one wheelassembly is adapted to transfer propelling torque from the at least onemotion actuator to the wheel of the at least one wheel assembly.
 19. Thevehicle of claim 18, wherein the wheel drive assembly further comprisesan inner CV joint mounted onto an inner end of the drive axle, the innerCV joint being functionally coupled to the output shaft of the motionactuator.
 20. The vehicle of claim 19, wherein the inner CV joint isdisposed at a laterally exterior edge of the chassis.
 21. The vehicle ofclaim 19 or claim 20, wherein the inner CV joint is verticallystationary with respect to the chassis, and the outer CV joint isvertically movable with respect to the chassis, within a predeterminedangular range of the drive axle relative to the chassis.
 22. The vehicleof any one of claims 19 to 21, wherein the motion actuator is attachedto the chassis, and functions as a sprung mass.
 23. A vehicle,comprising: a chassis; at least one motion actuator, functionallyassociated with the chassis, the motion actuator having an output shaft;and at least one wheel assembly, including: a wheel-hub arranged about alongitudinal axis; a drive axle; a constant velocity (CV) joint mountedonto an outer end of the drive axle, the CV joint connecting the driveaxle to the wheel-hub; and a wheel including a tire and a tire rim, thetire rim mounted onto the wheel-hub such that the longitudinal axis ofthe wheel-hub coincides with a rotational axis of the wheel, the wheelassembly being functionally associated with the output shaft of themotion actuator, as the source shaft, and the drive axle and CV jointare adapted to transfer propelling torque from the at least one motionactuator to the wheel; and a steering assembly, functionally associatedwith the wheel-hub and adapted to steer the wheel by pivoting thewheel-hub and the wheel about a steering pivot point, wherein thesteering pivot point does not coincide with a pivot point of the CVjoint.
 24. The vehicle of claim 23, wherein, when the steering assemblysteers the wheel hub at a steering angle δ, the CV joint swings at aswing angle γ, swing angle γ being smaller than steering angle δ.
 25. Avehicle, comprising: a chassis; at least one motion actuator,functionally associated with the chassis, the motion actuator having anoutput shaft; and at least one wheel assembly, including: a wheel-hubarranged about a longitudinal axis; a drive axle; a constant velocity(CV) joint mounted onto an outer end of the drive axle, the CV jointconnecting the drive axle to the wheel-hub; and a wheel including a tireand a tire rim, the tire rim mounted onto the wheel-hub, the wheelassembly being functionally associated with the output shaft of themotion actuator, as the source shaft, and the drive axle and CV jointare adapted to transfer propelling torque from the at least one motionactuator to the wheel; and a steering assembly, functionally associatedwith the wheel-hub and adapted to steer the wheel by pivoting thewheel-hub and the wheel about a steering pivot point, wherein thesteering pivot point does not coincide with a pivot point of the CVjoint, wherein, when the steering assembly steers the wheel hub at asteering angle δ, the CV joint swings at a swing angle γ, swing angle γbeing smaller than steering angle δ.
 26. The vehicle of claim 24 orclaim 25, wherein a ratio between swing angle γ and steering angle δ isnot greater than 1:1.5.
 27. The vehicle of any one of claims 23 to 26,wherein an outermost surface of the CV joint is disposed outwardly of anoutermost surface of the wheel hub, along the longitudinal axis of thewheel-hub.
 28. The vehicle of any one of claims 23 to 27, wherein atleast a portion of the CV joint is visible from an outer side of thewheel.
 29. The vehicle of any one of claims 23 to 28, wherein the wheeldrive assembly further comprises an inner CV joint mounted onto an innerend of the drive axle, the inner CV joint being functionally coupled tothe output shaft of the motion actuator.
 30. The vehicle of claim 29,wherein the inner CV joint is disposed at a laterally exterior edge ofthe chassis.
 31. The vehicle of claim 29 or claim 30, wherein the innerCV joint is vertically stationary with respect to the chassis, and theouter CV joint is vertically movable with respect to the chassis, withina predetermined angular range of the drive axle relative to the chassis.32. The vehicle of any one of claims 23 to 31, wherein the motionactuator is attached to the chassis, and functions as a sprung mass. 33.A method for enabling transfer of propelling torque from a motionactuator of a vehicle, having an output shaft, to a wheel of thevehicle, using a drive shaft, a the method comprising: fastening anouter CV joint of the drive shaft to an outer side of the wheel-hub;connecting an inner CV joint of the drive shaft to the output shaft ofthe motion actuator; and mounting a wheel on the wheel hub, wherein,following the fastening, an outermost surface of the CV joint isdisposed outwardly of an outermost surface of the wheel hub.
 34. Themethod of claim 33, the mounting of the wheel on the wheel hub occursprior to the fastening of the outer CV joint.
 35. The method of any oneof claims 33 to 34, further comprising, prior to the fastening,inserting the outer CV joint into the wheel hub from an exterior side ofthe wheel hub.
 36. The method of claim 35, wherein the wheel-hubincludes an outer-side seat, and the inserting of the outer CV jointcomprises accommodating the outer CV joint in the outer-side seat. 37.The method of any one of claims 33 to 36, wherein the wheel comprises atire mounted onto a tire rim, and the mounting of the wheel on the wheelhub comprises fastening the tire rim to the wheel-hub.
 38. The method ofclaim 37, wherein the outermost surface of the outer CV joint extendsoutwardly of a central portion of the tire rim.
 39. The method of claim37 or claim 38, wherein the outermost surface of the outer CV jointextends outwardly of the majority of the tire rim.
 40. The method of anyone of claims 37 to 39, wherein the outermost surface of the outer CVjoint extends outwardly of the entirety of the tire rim.
 41. The methodof claims 33 to 40, wherein the connecting an inner CV joint comprisesplacing the inner CV joint at an exterior edge of a chassis of thevehicle.